linux-kernel - [PATCH 05/11] early_printk: Allow more than one early console

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 20 Aug 2009 15:39:52 -0500
From:	Jason Wessel <jason.wessel@...driver.com>
To:	gregkh@...e.de
Cc:	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	Jason Wessel <jason.wessel@...driver.com>,
	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Yinghai Lu <yinghai@...nel.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Randy Dunlap <randy.dunlap@...cle.com>
Subject: [PATCH 05/11] early_printk: Allow more than one early console

It is desirable to be able to use one early boot device to debug
another or to have multiple places you can see the early boot
diagnostics, such as the vga screen or serial device.

This patch changes the early_printk console device registration to
allow more than one early printk device to get registered via
register_console().

Signed-off-by: Jason Wessel <jason.wessel@...driver.com>
Cc: Greg KH <gregkh@...e.de>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Yinghai Lu <yinghai@...nel.org>
Cc: "Eric W. Biederman" <ebiederm@...ssion.com>
Cc: Randy Dunlap <randy.dunlap@...cle.com>
---
 arch/x86/kernel/early_printk.c |   65 ++++++++++++++++++++-------------------
 1 files changed, 33 insertions(+), 32 deletions(-)

diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
index 519a5e1..2acfd3f 100644
--- a/arch/x86/kernel/early_printk.c
+++ b/arch/x86/kernel/early_printk.c
@@ -176,10 +176,19 @@ asmlinkage void early_printk(const char *fmt, ...)
 	va_end(ap);
 }
 
+static inline void early_console_register(struct console *con, int keep_early)
+{
+	early_console = con;
+	if (keep_early)
+		early_console->flags &= ~CON_BOOT;
+	else
+		early_console->flags |= CON_BOOT;
+	register_console(early_console);
+}
 
 static int __init setup_early_printk(char *buf)
 {
-	int keep_early;
+	int keep;
 
 	if (!buf)
 		return 0;
@@ -188,42 +197,34 @@ static int __init setup_early_printk(char *buf)
 		return 0;
 	early_console_initialized = 1;
 
-	keep_early = (strstr(buf, "keep") != NULL);
-
-	if (!strncmp(buf, "serial", 6)) {
-		early_serial_init(buf + 6);
-		early_console = &early_serial_console;
-	} else if (!strncmp(buf, "ttyS", 4)) {
-		early_serial_init(buf);
-		early_console = &early_serial_console;
-	} else if (!strncmp(buf, "vga", 3)
-		&& boot_params.screen_info.orig_video_isVGA == 1) {
-		max_xpos = boot_params.screen_info.orig_video_cols;
-		max_ypos = boot_params.screen_info.orig_video_lines;
-		current_ypos = boot_params.screen_info.orig_y;
-		early_console = &early_vga_console;
+	keep = (strstr(buf, "keep") != NULL);
+
+	while (*buf != '\0') {
+		if (!strncmp(buf, "serial", 6)) {
+			early_serial_init(buf + 6);
+			early_console_register(&early_serial_console, keep);
+		}
+		if (!strncmp(buf, "ttyS", 4)) {
+			early_serial_init(buf + 4);
+			early_console_register(&early_serial_console, keep);
+		}
+		if (!strncmp(buf, "vga", 3) &&
+		    boot_params.screen_info.orig_video_isVGA == 1) {
+			max_xpos = boot_params.screen_info.orig_video_cols;
+			max_ypos = boot_params.screen_info.orig_video_lines;
+			current_ypos = boot_params.screen_info.orig_y;
+			early_console_register(&early_vga_console, keep);
+		}
 #ifdef CONFIG_EARLY_PRINTK_DBGP
-	} else if (!strncmp(buf, "dbgp", 4)) {
-		if (early_dbgp_init(buf+4) < 0)
-			return 0;
-		early_console = &early_dbgp_console;
-		/*
-		 * usb subsys will reset ehci controller, so don't keep
-		 * that early console
-		 */
-		keep_early = 0;
+		if (!strncmp(buf, "dbgp", 4) && !early_dbgp_init(buf + 4))
+			early_console_register(&early_dbgp_console, keep);
 #endif
 #ifdef CONFIG_HVC_XEN
-	} else if (!strncmp(buf, "xen", 3)) {
-		early_console = &xenboot_console;
+		if (!strncmp(buf, "xen", 3))
+			early_console_register(&xenboot_console, keep);
 #endif
+		buf++;
 	}
-
-	if (keep_early)
-		early_console->flags &= ~CON_BOOT;
-	else
-		early_console->flags |= CON_BOOT;
-	register_console(early_console);
 	return 0;
 }
 
-- 
1.6.3.1.9.g95405b

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/